President Obama and Chuck Hagel / Pablo Martinez Monsivais, AP

by David Jackson and Susan Davis, USA TODAY

by David Jackson and Susan Davis, USA TODAY

Senate Republicans blocked a confirmation vote Thursday on Defense Secretary nominee Chuck Hagel, even as Democrats and the White House blasted the prospect of a historic filibuster.

"These delaying tactics are unconscionable and they should end right away," said White House spokesman Josh Earnest, adding that the nation and the world need a leader in the Pentagon as soon as possible.

Senate Majority Leader Harry Reid, D-Nev., called a procedural vote Thursday to end debate and allow a vote on the nomination, but GOP opposition prevented him from getting the 60 votes necessary.

Republicans want to delay Hagel's nomination until after the President's Day recess but leading senators have pledged to allow an up or down vote when the Senate returns the week of Feb. 25.

"I will vote in favor of cloture on the day we get back," said Sen. John McCain, R-Ariz., who echoed the majority view of GOP senators Thursday who said they would oppose any effort to end debate and vote on the nomination this week.

"Senators have questions -- we have a right to have answers," said Sen. Lamar Alexander, R-Tenn. "I think in the end you should vote up or down on cabinet nominees, but I don't think you should prematurely cut off debate of the United States Secretary of Defense nomination two days after it comes out of committee."

In protesting the delay, Reid noted there has never been a filibuster of a Defense secretary nominee, and he called the potential development "shocking" and "tragic."

Republicans senators said they have a variety of concerns and requests for more information.

Sen. Lindsey Graham, R-S.C., cited reports that Hagel said in a 2007 speech that the State Department was controlled by Israel. Sen. Ted Cruz, R-Texas, has sought more information on Hagel's financial records.

Republicans have also sought more specific information from President Obama about the deadly Sept. 11 attack on the U.S. Consulate in Benghazi, Libya.

"We voted for Sen. Kerry on the same day because we were comfortable," Graham said. "We are not all comfortable here. This is a controversial nominee and a party line vote. There is a desire to not end debate now."

Hoping to coax some Republicans, the White House counsel's office sent a letter on Benghazi to three key Republican critics, Sens. Graham, John McCain of Arizona and Kelly Ayotte of New Hampshire.

The letter said that President Obama did not call Libyan President Mohamed Magariaf on the day of the Benghazi attack, Sept. 11, but had Secretary of State Hillary Rodham Clinton call the Libyan leader; Obama spoke to Magariaf the next day, Sept. 12.

Throughout the confirmation process, some Republicans have criticized Hagel -- a former GOP senator from Nebraska -- by saying he has been too critical of Israel and too soft on Iran and its nuclear ambitions. Some also cited what they called Hagel's poor performance during his confirmation hearing.

During his confirmation hearing, Hagel -- who would replace retiring Defense Secretary Leon Panetta -- said he supports Israel's national security, and would work to block Iran from obtaining the means to make a nuclear weapon.

Hagel clearly has the votes to be confirmed, Reid said, but Republicans are seeking excuses to delay this and other Obama initiatives. "The pattern has been clear for months," Reid said, "as soon as President Obama's administration responds to one request, Republicans devise another, more outlandish request."

At the White House, officials said the Pentagon faces challenges that require a new Defense secretary.

Earnest noted that the military faces massive budget cuts as part of the $85 billion budget sequester set to take effect March 1 unless the White House and Congress reach a new debt reduction deal.

Global defense ministers are scheduled to meet in Brussels next week to discuss the Afghanistan withdrawal, Earnest said, and "we need our new defense secretary to be there."

The administration has consulted closely with senators from both parties on the Hagel nomination, Earnest said, including more than 10,000 pages of documents. "Ten different congressional hearings on Benghazi in particular have been held," he said.

White House officials said Republicans are only re-litigating the debate over the Iraq War, which Hagel initially supported and then turned against.

Earnest pointed out that Hagel is a Republican now being blocked by Republicans, and that does not send "a favorable signal" to the world.